Enclosed cups having drinking spouts and separate air vents, which allow the user to drink from the spout without creating excessive vacuum in the cup, are known in the art. However, drinking spouts and air vents are liable to leak liquid stored in the cup between feedings, or if dropped during use. Accordingly, certain cups have been developed that use valving mechanisms at the spout and at the air vent. These valves respond to suction generated during feeding to open and allow liquid to pass through the spout and to allow air to enter the air vent when a vacuum is developed in the interior of the cup.
Two patents disclosing such valves are U.S. Pat. No. 5,079,013 to Belanger and U.S. Pat. No. 5,542,670 to Morano, both commonly assigned or licensed to the assignee of the present application. Applicant hereby incorporates the disclosure of those two patents herein by reference. Applicant has on the market a cup that employs a valve assembly similar to that shown in U.S. Pat. No. 5,079,013 that is secured to sleeves in the underside of the cup's top, but in which the valves are mounted on a single base element. Applicant is also aware of a competitive product having a flow control element of the configuration depicted in FIG. 1, sold as part of the Tumble Mates Spill Proof Cup by the First Years.
Despite the effectiveness of these cup mechanisms, applicant has discovered an improved flow control element and corresponding valve configuration that provides improved fluid flow rates without sacrificing the valve's resistance to spills or the valve's durability.